From 02fed471a4568852d6618e041c4f2af0d7730ee2 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Thu, 29 Aug 2013 15:29:02 -0400
Subject: [PATCH] Implements fixed-point silk_LPC_analysis_filter() in terms of
celt_fir()
Saves 2.5% on ARM without any asm. The float build still uses the old
code because celt_fir() then becomes a float function.
---
celt/arch.h | 1 +
celt/celt_lpc.c | 13 ++++++-------
celt/fixed_generic.h | 2 ++
silk/LPC_analysis_filter.c | 23 ++++++++++++++++++++++-
4 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/celt/arch.h b/celt/arch.h
index e497a4d92..78e2635f0 100644
--- a/celt/arch.h
+++ b/celt/arch.h
@@ -163,6 +163,7 @@ typedef float celt_ener;
#define SHR(a,shift) (a)
#define SHL(a,shift) (a)
#define SATURATE(x,a) (x)
+#define SATURATE16(x) (x)
#define ROUND16(a,shift) (a)
#define HALF16(x) (.5f*(x))
diff --git a/celt/celt_lpc.c b/celt/celt_lpc.c
index 523c36aae..7ffe90a35 100644
--- a/celt/celt_lpc.c
+++ b/celt/celt_lpc.c
@@ -118,25 +118,24 @@ void celt_fir(const opus_val16 *_x,
{
sum = MAC16_16(sum,rnum[j],x[i+j]);
}
- _y[i] = ROUND16(sum, SIG_SHIFT);
+ _y[i] = SATURATE16(PSHR32(sum, SIG_SHIFT));
}
#else
- celt_assert((ord&3)==0);
for (i=0;i<N-3;i+=4)
{
opus_val32 sum[4]={0,0,0,0};
xcorr_kernel(rnum, x+i, sum, ord);
- _y[i ] = ADD16(_x[i ], ROUND16(sum[0], SIG_SHIFT));
- _y[i+1] = ADD16(_x[i+1], ROUND16(sum[1], SIG_SHIFT));
- _y[i+2] = ADD16(_x[i+2], ROUND16(sum[2], SIG_SHIFT));
- _y[i+3] = ADD16(_x[i+3], ROUND16(sum[3], SIG_SHIFT));
+ _y[i ] = SATURATE16(ADD32(EXTEND32(_x[i ]), PSHR32(sum[0], SIG_SHIFT)));
+ _y[i+1] = SATURATE16(ADD32(EXTEND32(_x[i+1]), PSHR32(sum[1], SIG_SHIFT)));
+ _y[i+2] = SATURATE16(ADD32(EXTEND32(_x[i+2]), PSHR32(sum[2], SIG_SHIFT)));
+ _y[i+3] = SATURATE16(ADD32(EXTEND32(_x[i+3]), PSHR32(sum[3], SIG_SHIFT)));
}
for (;i<N;i++)
{
opus_val32 sum = 0;
for (j=0;j<ord;j++)
sum = MAC16_16(sum,rnum[j],x[i+j]);
- _y[i] = ADD16(_x[i ], ROUND16(sum, SIG_SHIFT));
+ _y[i] = SATURATE16(ADD32(EXTEND32(_x[i]), PSHR32(sum, SIG_SHIFT)));
}
#endif
RESTORE_STACK;
diff --git a/celt/fixed_generic.h b/celt/fixed_generic.h
index ac01a4345..0e77976e8 100644
--- a/celt/fixed_generic.h
+++ b/celt/fixed_generic.h
@@ -84,6 +84,8 @@
#define PSHR(a,shift) (SHR((a)+((EXTEND32(1)<<((shift))>>1)),shift))
#define SATURATE(x,a) (((x)>(a) ? (a) : (x)<-(a) ? -(a) : (x)))
+#define SATURATE16(x) (EXTRACT16((x)>32767 ? 32767 : (x)<-32768 ? -32768 : (x)))
+
/** Shift by a and round-to-neareast 32-bit value. Result is a 16-bit value */
#define ROUND16(x,a) (EXTRACT16(PSHR32((x),(a))))
/** Divide by two */
diff --git a/silk/LPC_analysis_filter.c b/silk/LPC_analysis_filter.c
index e2c0c88b1..9bfeba0f5 100644
--- a/silk/LPC_analysis_filter.c
+++ b/silk/LPC_analysis_filter.c
@@ -30,6 +30,7 @@ POSSIBILITY OF SUCH DAMAGE.
#endif
#include "SigProc_FIX.h"
+#include "celt_lpc.h"
/*******************************************/
/* LPC analysis filter */
@@ -46,14 +47,33 @@ void silk_LPC_analysis_filter(
const opus_int32 d /* I Filter order */
)
{
- opus_int ix, j;
+ opus_int j;
+#ifdef FIXED_POINT
+ opus_int16 mem[SILK_MAX_ORDER_LPC];
+ opus_int16 num[SILK_MAX_ORDER_LPC];
+#else
+ int ix;
opus_int32 out32_Q12, out32;
const opus_int16 *in_ptr;
+#endif
silk_assert( d >= 6 );
silk_assert( (d & 1) == 0 );
silk_assert( d <= len );
+#ifdef FIXED_POINT
+ silk_assert( d <= SILK_MAX_ORDER_LPC );
+ for ( j = 0; j < d; j++ ) {
+ num[ j ] = -B[ j ];
+ }
+ for (j=0;j<d;j++) {
+ mem[ j ] = in[ d - j - 1 ];
+ }
+ celt_fir( in + d, num, out + d, len - d, d, mem );
+ for ( j = 0; j < d; j++ ) {
+ out[ j ] = 0;
+ }
+#else
for( ix = d; ix < len; ix++ ) {
in_ptr = &in[ ix - 1 ];
@@ -82,4 +102,5 @@ void silk_LPC_analysis_filter(
/* Set first d output samples to zero */
silk_memset( out, 0, d * sizeof( opus_int16 ) );
+#endif
}
--
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